Field of the Invention
This disclosure relates to improved self-locking or ligatureless orthodontic brackets.
Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Several self-locking or self-ligating (ligatureless) orthodontic brackets have been designed. However, most of those have complex designs, incorporating features requiring prohibitively expensive machining operations or comprising multiple separate parts, which in turn increases the number of failure modes for such brackets. Other designs have been rejected in the marketplace due to poor quality or poor design, a lack of available features, difficulty of use, or other factors.
One such bracket is disclosed in U.S. Pat. No. 7,621,743 entitled Orthodontic Bracket. That device is a self-ligating bracket that includes a locking slide cover that entrains an archwire. However, like many sliding covers, the top surface is not smooth, which is important for patient comfort. Moreover, this device is difficult to manufacturer requiring small interlocking extensions mating in the plane of the slide and guide members on either side having sharp edges that protrude outwardly which have a tendency to irritate the mouth of the user.
Another construction is shown in U.S. Pat. No. 8,414,292. In this patent, a keyhole-shaped clip slides across an archwire slot and two wings on the clip engage stops to lock the clip in place. The locking clip is tiny, and because it is flat, it is rather flimsy and prone to failure.